Do you have an external disk you can copy sda to and experiment on?
Disk /dev/sda - 480 GB / 447 GiB - CHS 58369 255 63 Partition Start End Size in sectors P EFI System 40 409639 409600 [EFI System Partition]P Mac HFS 409640 700519039 700109400P Linux filesys. data 700520448 759113727 58593280 P Linux Swap 759113728 761114607 2000880 P Linux filesys. data 761114624 937701375 176586752
# fdisk -l Disk /dev/sda: 447,13 GiB, 480103981056 bytes, 937703088 sectorsDisk model: CT480BX500SSD1 Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: gpt Disk identifier: 20F7D036-E7D4-4247-9944-2190A2A933AE Device Start End Sectors Size Type /dev/sda3 700520448 759113727 58593280 27,9G Linux filesystem /dev/sda4 759113728 761114623 2000896 977M Linux swap /dev/sda5 761114624 937701375 176586752 84,2G Linux filesystem
Looks like sda1 and sda2 are missing from the partition table. If it's just that then putting that back but changing nothing else is all that is needed. I'd use fdisk to do it, but other tools might be easier/less error prone. But making a disk level backup first is strongly recommended! It's really easy to make things worse. It's not obvious to me why there is a gap between the end of the HFS partition and the start of sda3. That might be expected or might mean the sector numbers aren't quite right... Tim.